Magnesium-based solid-state cyclic hydrogen storage system using low-cost electricity and working method thereof

Abstract

The application discloses a magnesium-based solid-state cycle hydrogen storage and release system using low-cost electricity and a working method thereof. The magnesium-based solid-state cycle hydrogen storage and release system comprises a heat storage device, a magnesium-based solid-state cycle hydrogen storage and release device and a heat conducting medium circulation system. The heat storage device is internally provided with a heat storage component, and the heat storage component is provided with a first heat conducting medium channel. The magnesium-based solid-state cycle hydrogen storage and release device is provided with a second heat conducting medium channel. The heat conducting medium circulation system is used for connecting the first heat conducting medium channel and the second heat conducting medium channel. In the period of sufficient electricity and lower price than the average price of the general power grid, the electric energy is converted into heat and stored in the heat storage device. When the magnesium-based solid-state cycle hydrogen storage and release device needs heat, the heat storage device relies on the heat conducting medium to transfer heat to the magnesium-based solid-state cycle hydrogen storage and release device. The application can consume a large amount of valley electricity, wind power and photovoltaic power, and is energy-saving, environment-friendly and pollution-free.

Description

TECHNICAL FIELD

[0001] The present application relates to a magnesium-based solid-state cyclic hydrogen storage system, in particular, a system for releasing hydrogen by using low-cost electricity (wind power, photovoltaic power, off-peak power, etc.) to heat, storing heat by a heat storage device, and heating a magnesium-based solid-state cyclic hydrogen storage device, thereby releasing hydrogen, and belongs to the technical field of hydrogen energy. BACKGROUND

[0002] Low-cost electricity includes off-peak power, wind power, photovoltaic power, etc. At present, the power grid price during the peak electricity consumption period is 1 yuan / degree, while the price of a large amount of off-peak power is 0.25-0.3 yuan / degree. Off-peak power refers to the power generated from 22:00 to 8:00 the next day, lasting a total of 10 hours, and off-peak power is greatly limited by time. The price of photovoltaic power and wind power is also 0.25-0.3 yuan / degree. Solar power generation and wind power generation are greatly affected by day and night, weather conditions, and seasonal changes, and have significant discontinuous, unstable, and uncontrollable non-steady-state characteristics.

[0003] The instability of photovoltaic power and wind power and the fluctuation of grid load are superimposed, increasing the difficulty of grid dispatching. When the proportion of new energy power generation is small, conventional power sources can basically compensate for these power fluctuations in real time. However, when a large amount of new energy is connected to the grid, the power fluctuation amplitude is large, which may exceed the adjustment capability limit of conventional power sources, resulting in difficulty in power balance and reduction of power supply reliability and grid operation stability. The above reasons result in a large amount of photovoltaic power and wind power being unable to be connected to the grid.

[0004] The magnesium-based solid-state cyclic hydrogen storage system consumes a large amount of electricity during operation. The magnesium-based solid-state hydrogen storage material is decomposed by heat to release hydrogen, and this hydrogen release process generally uses an electric heating method (electric heating tube or electric heating heat transfer oil furnace) to directly heat the solid-state hydrogen storage device without an energy storage process.

[0005] The main problems of the existing magnesium-based solid-state cyclic hydrogen storage system are:

[0006] (1) Directly using industrial electricity to heat the solid-state hydrogen storage device by an electric heater or an electric heating heat transfer oil furnace, the average electricity price cost is as high as 1 yuan / degree. The solid-state hydrogen storage process requires a large amount of heat energy, resulting in a high operating cost of the system.

[0007] (2) The traditional heating method uses an electric heating tube with a small area and low heat transfer efficiency. When the hydrogen storage system needs to store a large amount of hydrogen, a large number of electric heating tubes need to be set, and the equipment is more complex. On the other hand, during hydrogen storage, the hydrogen charging and cooling process is difficult, and the hydrogen charging time is long.

[0008] (3) The conventional heating is carried out by using heat conducting oil, and the maximum temperature of the heat conducting oil medium is generally 330 DEG C, which is relatively low, and the solid hydrogen release time process is long. If the temperature of the heat conducting oil is further increased, the heat conducting oil will deteriorate, and the service life will be shortened. SUMMARY

[0009] The technical problem to be solved by the present application is that the existing magnesium-based solid-state cyclic hydrogen storage system has high electricity cost, while a large amount of low-cost electricity such as valley electricity, wind power and photovoltaic electricity is in surplus, which cannot be easily absorbed by the power grid, resulting in energy waste.

[0010] To solve the above technical problems, the first aspect of the present application provides a magnesium-based solid-state cyclic hydrogen storage system using low-cost electricity, comprising a heat storage device, a magnesium-based solid-state cyclic hydrogen storage device, and a heat conducting medium circulation system.

[0011] The heat storage device is internally provided with a heat storage component, and the heat storage component is provided with a first heat conducting medium channel.

[0012] The magnesium-based solid-state cyclic hydrogen storage device is provided with a second heat conducting medium channel.

[0013] The heat conducting medium circulation system is used to connect the first heat conducting medium channel and the second heat conducting medium channel.

[0014] In some embodiments, the heat storage device is further internally provided with an electric heating component, and the electric heating component is heated by using low-cost electricity. The low-cost electricity refers to the electricity whose price is lower than the average price of the ordinary power grid.

[0015] In some embodiments, a gas is used as the heat conducting medium to circulate in the heat conducting medium circulation system, and the heat of the heat storage device is brought to the magnesium-based solid-state cyclic hydrogen storage device.

[0016] In some embodiments, the heat storage component comprises magnesium bricks or ceramics.

[0017] In some embodiments, the heat conducting medium circulation system is composed of a heat conducting medium circulation pipeline, a heat conducting medium power device and a heat conducting medium control device. The heat conducting medium power device provides power for the flow of the heat conducting medium, and the heat conducting medium control device is used to control the flow direction and flow rate of the heat conducting medium.

[0018] In some embodiments, the heat conducting medium circulation pipeline comprises a main loop and a bypass. The first end of the bypass is connected to the main loop through the heat conducting medium control device, and the second end of the bypass is connected to the main loop between the heat storage device and the magnesium-based solid-state cyclic hydrogen storage device.

[0019] In some embodiments, a first temperature sensor is installed on the main loop downstream of the heat storage device, a second temperature sensor is installed on the main loop upstream of the magnesium-based solid-state cyclic hydrogen storage device, and a third temperature sensor is installed on the bypass.

[0020] In some embodiments, the low-cost power device further comprises a low-cost power device that provides power at a price lower than the average price of ordinary power grid.

[0021] In some embodiments, the low-cost power device comprises a combination of one or more of a wind power device, a solar power device, and a hydroelectric power device.

[0022] In a second aspect of the present application, a method for operating the above-mentioned magnesium-based solid-state cyclic hydrogen storage system is provided, comprising the following steps:

[0023] Step one, during periods of sufficient and low-cost power, convert electrical energy into heat and store it in the heat storage device;

[0024] Step two, when the magnesium-based solid-state cyclic hydrogen storage device needs heat, the heat storage device transfers heat to the magnesium-based solid-state cyclic hydrogen storage device through the heat-conducting medium circulating in the heat-conducting medium circulation system.

[0025] The present application can absorb a large amount of off-peak electricity, wind power, and photovoltaic power, and is energy-saving, environmentally friendly, and pollution-free. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of the magnesium-based solid-state cyclic hydrogen storage system provided by a preferred embodiment of the present application.

[0027] Figure 2 is a schematic diagram of the working process of the magnesium-based solid-state cyclic hydrogen storage system provided by a preferred embodiment of the present application.

[0028] Figure 3 is a schematic diagram of the structure of the heat storage device in the magnesium-based solid-state cyclic hydrogen storage system provided by a preferred embodiment of the present application.

[0029] 100 low-cost power supply system

[0030] 200 power transmission system

[0031] 300 heat storage device

[0032] 301 solid magnesium brick

[0033] 302 mullite

[0034] 303 vermiculite plate

[0035] 304 insulation block

[0036] 305 base

[0037] 306 control box

[0038] 307 rock wool purification plate

[0039] 400 magnesium-based solid-state cyclic hydrogen storage device

[0040] 401 hydrogen inlet and outlet pipe

[0041] 511-516 high-temperature gas pipeline

[0042] 520 high-temperature gas control device

[0043] 530 high-temperature gas power device

[0044] 601-603 temperature sensor DETAILED DESCRIPTION

[0045] The terms "first", "second", and similar terms used in the description and the claims are not intended to denote any order, quantity, or importance, but are used to distinguish different components. The terms "one" or "a" or similar terms do not denote a quantity limitation, but mean that at least one exists. In the description of the patent, the meaning of "a plurality" is two or more, unless otherwise specified.

[0046] The terms "include" or "have" or similar terms mean that the elements or objects appearing before the "include" or "have" cover the elements or objects listed after the "include" or "have" and their equivalent elements, and do not exclude other elements or objects.

[0047] In the description of the patent, unless otherwise specified and limited, the terms "mount", "connect", and "connect" can be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected. It can be mechanically connected, or it can be electrically connected. It can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the patent can be understood according to the specific circumstances.

[0048] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0049] The overall structure of the magnesium-based solid-state cyclic hydrogen storage system provided by the present application is as shown in Figure 1As shown, it is a system that uses low-cost electricity to heat the solid cycle hydrogen storage device by energy storage. In addition to common wind power, photovoltaic power, off-peak power, etc., all electricity below the normal grid price can be called low-cost electricity, which can also be used in this system, such as hydropower, lithium battery storage, etc.

[0050] The working principle of the magnesium-based solid-state cycle hydrogen storage system provided by the application is as shown in Figure 2 As shown, it uses low-cost electricity (photovoltaic power, wind power, off-peak power, etc.) to heat the heat storage device. The heat storage device has solid magnesium bricks, heat storage ceramics and other solid heat storage materials inside, which are used to store the heat. The heat storage device is connected to the magnesium-based solid-state cycle hydrogen storage device through a circulating pipeline system. The heat-conducting medium in the circulating pipeline is gas. When the magnesium-based solid-state cycle hydrogen storage device needs heat, the gas in the circulating pipeline flows, and the gas is heated by the heat storage device to become high-temperature gas. The high-temperature gas flows through the magnesium-based solid-state cycle hydrogen storage device and releases heat to it. The high-temperature gas cools down and flows to the heat storage device, and the cycle continues, so that the heat in the heat storage device is continuously brought to the magnesium-based solid-state cycle hydrogen storage device.

[0051] The structure diagram of the magnesium-based solid-state cycle hydrogen storage system is as shown in Figure 1 The magnesium-based solid-state cycle hydrogen storage system includes a low-cost power supply system 100 using solar energy, wind power or off-peak power. The low-cost power supply system 100 can use one of solar energy, wind power and off-peak power alone; or use a combination of two or even three of solar energy, wind power and off-peak power to make up for the shortcomings of single use. When it uses a wind power device, it should include a wind power generation device as shown on the far left. When it uses a photovoltaic power device, it should include a solar panel and other necessary equipment for converting solar energy into electrical energy. Figure 1

[0052] The unique feature of the magnesium-based solid-state cycle hydrogen storage system provided by the application is the use of a heat storage device 300. The heat storage device 300 has an electric heating component (not shown in the figure) inside. The heat storage device 300 converts low-cost electricity such as wind power, photovoltaic power and off-peak power affected by time, weather, etc. into heat energy through the built-in electric heating component, and stores it inside the heat storage device 300.

[0053] The heat storage device 300 is connected to the low-cost power supply system 100 through a power transmission system 200, which includes wires, transformers, switches (not shown in the figure) and the like, and if necessary, can also include AC / DC converters and the like. The low-cost power supply system 100 supplies power to the electric heating component, which emits a large amount of heat, which is stored in the solid magnesium bricks 301 inside the heat storage device 300, as shown in Figure 3 ​The solid magnesium bricks 301 are wrapped by multiple layers of thermal insulation materials, which can keep the heat in the heat storage device 300 for a long time. The first layer of thermal insulation material outside the solid magnesium bricks 301 is mullite 302, the second layer of thermal insulation material outside the mullite 302 is vermiculite board 303, the third layer of thermal insulation material outside the vermiculite board 303 is thermal insulation block 304, and the fourth layer of thermal insulation material outside the thermal insulation block 304 is rock wool purification board 307. The heat storage device 300 is provided with a base 305 at the lower part, and a control box 306 is installed on the side of the heat storage device 300.

[0054] The heat storage device 300 is provided with a gas inlet and a gas outlet. The gas inlet is connected with the high-temperature gas pipeline 515, and the gas outlet is connected with the high-temperature gas pipeline 511, as shown in Figure 1 In this embodiment, the heat storage body of the heat storage device 300 is the solid magnesium bricks 301. The solid magnesium bricks 301 have gas channels therein. When the gas flows through the gas channels in the solid magnesium bricks 301, the heat stored in the solid magnesium bricks 301 heats the gas to a very high temperature. The heat storage device 300 stores heat energy when there is a large amount of low-cost electricity. When the electricity cost is at a higher period, the heat storage device 300 supplies heat to the magnesium-based solid-state cyclic hydrogen storage and release device 400. In other embodiments, the heat storage body of the heat storage device can also be heat storage molten salt, heat storage ceramic, etc.

[0055] The magnesium-based solid-state cyclic hydrogen storage and release device 400 is provided with a heat-conducting medium channel therein, which can be used for the heat-conducting medium to flow therethrough, for heating or cooling the hydrogen storage magnesium alloy. The magnesium-based solid-state cyclic hydrogen storage and release device 400 is connected with the heat storage device 300 through a heat-conducting medium circulation system, as shown in Figure 1 The heat-conducting medium circulation system is composed of a high-temperature gas circulation pipeline, a high-temperature gas control device 520, a high-temperature gas power device 530, etc. The high-temperature gas circulation pipeline includes a main loop and a bypass. Figure 1 The main loop is composed of the high-temperature gas pipelines 511, 512, 513, 514, and 515 in Figure 1 The bypass is the high-temperature gas pipeline 516 in

[0056] The high-temperature gas pipeline 512 is connected with the magnesium-based solid-state cyclic hydrogen storage and release device 400, and the magnesium-based solid-state cyclic hydrogen storage and release device 400 is connected with the high-temperature gas pipeline 513. The magnesium-based solid-state cyclic hydrogen storage and release device 400 is not only a storage tank for the magnesium alloy material, but also a device for heat exchange with the high-temperature gas. The hydrogen inlet and outlet pipe 401 can be used for hydrogen charging and hydrogen releasing of the magnesium-based solid-state cyclic hydrogen storage and release device 400.

[0057] A temperature sensor 601 is installed on the high-temperature gas pipeline 511, a temperature sensor 602 is installed on the high-temperature gas pipeline 512, and a temperature sensor 603 is installed on the high-temperature gas pipeline 516. After passing through the magnesium-based solid-state cyclic hydrogen storage device 400, the gas temperature is still 320°C, and the above-mentioned main loop can make the waste heat of the 320°C high-temperature gas be recycled and utilized.

[0058] The high-temperature gas control device 520 can adopt an electrically controlled tee joint, which is installed in the main loop and connected with the bypass. By using the high-temperature gas control device 520, the outlet air temperature of the solid magnesium brick heat storage device 300 can be adjusted.

[0059] The high-temperature gas power device 530 is connected in the main loop of the circulation pipeline. Specifically, the high-temperature gas power device 530 is installed between the magnesium-based solid-state cyclic hydrogen storage device 400 and the high-temperature gas control device 520. Specifically, it is between the high-temperature gas pipeline 513 and the high-temperature gas pipeline 514 shown in FIG. 5. Figure 1 The high-temperature gas power device 530 can adopt a power fan, which provides power for the circulation flow of the high-temperature gas heat conduction medium.

[0060] The high-temperature gas pipeline 516 serves as a bypass, and its first end is connected to the main loop through the high-temperature gas control device 520, and its second end is connected to the main loop downstream of the heat storage device 300, that is, the high-temperature gas pipeline 511 or the high-temperature gas pipeline 512 in FIG. 5. Figure 1

[0061] The working mode of the magnesium-based solid-state cyclic hydrogen storage system provided in the embodiment is as follows:

[0062] (I) Energy storage

[0063] When the wind power, photovoltaic power, valley power and other electric powers are sufficient and the prices are relatively low (generally 0.3 yuan / degree, and the normal power grid price is 1 yuan / degree), the low-cost power supply system 100 stores heat in the heat storage device 300, and the electric energy is converted into heat energy for storage.

[0064] (II) Heating

[0065] When the magnesium-based solid-state cyclic hydrogen storage device 400 releases hydrogen, a large amount of heat is needed to heat the solid-state hydrogen storage magnesium alloy material therein, so as to make hydrogen escape from the solid-state hydrogen storage magnesium alloy material.

[0066] The air in the circulation pipeline is initially in a normal temperature state, at which time the high-temperature gas power device 530 needs to be turned on, so that the air passes through the high-temperature gas pipeline 514, the high-temperature gas control device 520, the high-temperature gas pipeline 515 and the heat storage device 300. After the normal temperature gas passes through the hole in the solid magnesium brick 301 of the heat storage device 300, the gas temperature is heated to above 450°C, and the gas becomes high-temperature air. ​

[0067] When the high-temperature air flows through the magnesium-based solid-state cyclic hydrogen storage device 400, the high-temperature air exchanges heat with the magnesium-based solid-state cyclic hydrogen storage device 400, and the heat of the high-temperature air is absorbed by the magnesium-based solid-state cyclic hydrogen storage device 400, so that the temperature of the high-temperature air decreases from 450°C to about 350°C. After absorbing the heat, the temperature of the magnesium-based solid-state cyclic hydrogen storage device 400 increases, and when the temperature reaches the decomposition temperature of the solid-state magnesium alloy material, hydrogen is released, and the hydrogen is discharged from the hydrogen inlet and outlet pipe 401.

[0068] (Three) Adjustment

[0069] When the temperature sensor 602 detects that the temperature of the high-temperature gas pipeline 512 is higher than the required temperature of the magnesium-based solid-state cyclic hydrogen storage device 400, the high-temperature gas control device 520 starts to adjust the air volume distribution: increase the gas flow of the high-temperature gas pipeline 516 and decrease the gas flow of the high-temperature gas pipeline 515. Increasing the gas flow of the high-temperature gas pipeline 515 means increasing the gas flow of the high-temperature gas pipeline 511. The gas in the high-temperature gas pipeline 511 is high-temperature air just discharged from the heat storage device 300, and the gas in the high-temperature gas pipeline 516 is low-temperature air. The temperature of the mixed gas meets the requirements of the magnesium-based solid-state cyclic hydrogen storage device 400.

[0070] When the temperature sensor 602 detects that the temperature of the high-temperature gas pipeline 512 is lower than the required temperature of the magnesium-based solid-state cyclic hydrogen storage device 400, the high-temperature gas control device 520 is adjusted to decrease the gas flow of the high-temperature gas pipeline 516 and increase the gas flow of the high-temperature gas pipeline 515. The principle is the same as above. The gas flow and temperature of the high-temperature gas pipeline 512 meet the use requirements of the magnesium-based solid-state cyclic hydrogen storage device 400.

[0071] The temperature sensor 601 monitors the temperature of the high-temperature gas pipeline 511 in real time and feeds back to the central controller (not shown in the figure), and the temperature sensor 603 monitors the temperature of the high-temperature gas pipeline 516 in real time and also feeds back to the central controller. The central controller calculates the appropriate opening degree of each path of the high-temperature gas control device 520, so that the mixed gas from the high-temperature gas pipeline 511 and the high-temperature gas pipeline 516 has a temperature that meets the requirements of the magnesium-based solid-state cyclic hydrogen storage device 400. The temperature sensor 602 detects the high-temperature gas pipeline 512 in real time and feeds back the result to the central controller, forming a control closed loop.

[0072] The magnesium-based solid-state cyclic hydrogen storage system provided by the application has the following advantages:

[0073] (1) Reducing the operation cost of the magnesium-based solid-state cyclic hydrogen storage device during use.

[0074] (2) Absorb a large amount of valley electricity, wind power, photovoltaic power and other power grid difficult to absorb production capacity.

[0075] (3) Explore and develop a new mode of integrated application of "wind, light, water, valley electricity + energy storage + hydrogen energy utilization", develop and promote new hydrogen mode, and make solid-state circulating hydrogen storage applicable to more different scenes.

[0076] (4) Compared with the electric heating pipe type hydrogen storage device, the magnesium-based solid-state circulating hydrogen storage system provided by the application does not need a large number of electric heating pipes, and the wiring is simple.

[0077] (5) Compared with the heat-conducting oil type hydrogen storage device, the heat-conducting medium in the magnesium-based solid-state circulating hydrogen storage system provided by the application adopts air, the temperature is higher (the maximum temperature of the heat-conducting oil medium is 330 DEG C, and the gas temperature can be higher than 450 DEG C), the heat exchange rate is increased, the heat exchange time is shortened, and the air medium has no cost.

[0078] The above describes the preferred embodiments of the application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment on the basis of the prior art according to the concept of the application should be within the protection scope determined by the claims.

Claims

1. A magnesium-based solid-state cyclic hydrogen storage system utilizing low-cost electricity, characterized in that, The application relates to a heat storage device, a magnesium-based solid-state cyclic hydrogen storage device and a heat conducting medium circulation system. The heat storage device is internally provided with a heat storage component, and the heat storage component is provided with a first heat conducting medium channel. The magnesium-based solid-state cyclic hydrogen storage device is provided with a second heat conducting medium channel. The heat conducting medium circulation system is used for connecting the first heat conducting medium channel and the second heat conducting medium channel. The heat storage device is used for storing heat, and the magnesium-based solid-state cyclic hydrogen storage device is used for storing hydrogen. The heat conducting medium circulation system is composed of a heat conducting medium circulation pipeline, a heat conducting medium power device and a heat conducting medium control device. The heat conducting medium circulation pipeline comprises a main loop and a bypass. The first end of the bypass is connected to the main loop through the heat conducting medium control device, and the second end of the bypass is connected to the main loop between the heat storage device and the magnesium-based solid-state cyclic hydrogen storage device.

2. The magnesium-based solid-state cyclic hydrogen storage system of claim 1, wherein, The heat storage device is internally provided with an electric heating component, and the electric heating component is heated by low-cost electricity.

3. The magnesium-based solid-state cyclic hydrogen storage system of claim 1, wherein, The low-cost electricity refers to electricity with a price lower than the average price of ordinary power grids.

4. The magnesium-based solid-state cyclic hydrogen storage system of claim 1, wherein, The heat storage component comprises magnesium bricks or ceramics.

5. The magnesium-based solid-state cyclic hydrogen storage system of claim 1, wherein, A first temperature sensor is installed on the main loop downstream of the heat storage device, a second temperature sensor is installed on the main loop upstream of the magnesium-based solid-state cyclic hydrogen storage device, and a third temperature sensor is installed on the bypass.

6. The magnesium-based solid-state cyclic hydrogen storage system of claim 5, wherein, The application further comprises a low-cost electricity device.

7. The method of operating a magnesium-based solid-state cyclic hydrogen storage system of claim 1, wherein, The low-cost electricity device comprises one or more combinations of wind power generation devices, solar power generation devices and water power generation devices. The application comprises the following steps: Step one: during a period of sufficient electricity and a price lower than the average price of ordinary power grids, electric energy is converted into heat and stored in the heat storage device. Step two: when the magnesium-based solid-state cyclic hydrogen storage device needs heat, the heat storage device transmits heat to the magnesium-based solid-state cyclic hydrogen storage device by means of the heat conducting medium circulating in the heat conducting medium circulation system.

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